In constructing their temples Greeks used [b]architraved[/b]: horizontal joistsare supported by colums.

When loaded a joist, supported in two points, will bend. The upper part will come under pressure, the lower part will come under traction. Stone can support very high pressure, but when it comes to traction resistance is reduced to 1/10th.[br]To reduce traction in a joist you just have two options:[br][list][*]You can use a larger joist.[/*][*]You can reduce the span.[/*][/list]

Het Parthenon is 30,9 m breed. Deze afmeting kan je onmogelijk overbruggen met één marmeren balk. De Grieken konden niet anders dan bijkomende zuilen plaatsen en de tempelbreedte verdelen in kleinere overspanningen.